Absorption refrigerating apparatus



July 6, 1937. s. F. ZELLHOEFER ABSORPTION REFRIGERATING APPARATUS Fiied Dec. 2, 1935 2 Sheets-Sheet 2 N VEN TOR.

GLEN/V F. ZELL HOEFER BY A a mm ATTORNEY.

Patented July 6, 1937 UNITED STATES PArE roFncs 2,085,931 ABSORPTION REFRIGERATING APPARATUS Glenn F. Zellhoefer, Bloomington, I11. Application December 2, 1935,, Serial No. 52,468

4 Claims. (01. 62-119) This invention relates to improvements in. the absorption type of refrigerating apparatus and more particularly to an improved heat exchanger therefor.

Refrigerating apparatus employing a gaseous refrigerant and a liquid solvent therefor in which the gas is absorbed in the solvent to form a solu tion and the refrigerant freed from the solution in a heater or still is termed an absorption refrigerating apparatus. Such apparatus necessarily includes an absorber wherein the solution is formed, a heater or still wherein the gaseous refrigerant is boiled off or expelled from the solution, means transferring the solution from the absorber to the heater, a heat exchanger through which the heated solvent returns from the heater to the absorber and through which the solution passes on its way to the heater, a rectifier, a condenser and a cooling coil through which the gaseous refrigerant passes from the heater before being returned to the absorber.

It is an object of this invention to provide an improved heat exchanger for such a system. A system of this type is disclosed more in detail in this applicant's prior application Serial No. 736,232, filedJuly 20, 1934.

- With this and other objects in view, reference is made to the accompanying sheets of drawingsillustrating an embodiment of this invention with the understanding that minor changes may be made without departing from the scope thereof.

In the drawings:

Figure 1 is a view in elevation of an apparatus of the class described,.including an embodiment of the improved heat exchanger, with parts broken away and partly in section.

Figure 2 is a detail top plan view of this improved heat exchanger with partsof the cover broken away and parts of the upper outer coils broken away to show the inner coils.

FigureS is a view in vertical section taken on the line 33, Figure 2, looking inthe direction" I V of the arrows, with parts shown in elevation. ""liii' bf "a'j'wat r t wer, n t hown, by pipe 3,1;

In the form shown, the improved heat ex- ""the absorber A, and from thence by pipe il:;to

changer is enclosed in a rectangular casing 1, preferably supported uponadjustable feet 2 arranged adjacent each corner. The heater H and absorber A are supported upon legs 3 and Q above the casing I with the condenser C arranged below the heater H and the rectifier R extending above the top' of the heater, and with the float chamber casing F depending from the under side of the absorber and solution circulation pump P supported upon the casing therebelow. The apparatus above described is preferably encased with a cover 5 which may be supported upon the heat exchanger casing l, as shown, or may embrace said casing and rest upon the floor.

Before describing in detail the improved heat exchanger, it is customary in absorption refrigerating apparatus to circulate the solution, through the outer coils'of the heat exchanger to the heater and to circulate the solvent in the opposite direction from the'heater through the inner coils of the heat exchanger and through a float valve before discharged into the absorber,

said float valve being controlled by the amount of solution collected within-the float valve casing solution pump P which discharges the solution through pipe I to a manifold M of the heat exchanger connected to the outer coils thereof, to be hereinafter described.

The pump P circulates the solution through the outer coils of the heat' exchanger to a manifold M from which it passes through pipe 8 to be discharged within the heater H. The gaseous refrigerant boiled off or expelled from the solution within the heater H passes through the rectifier R. and by pipe 9 into the condenser C, and after passing through the condenser the refrigerant in liquid form is conducted through pipe 80 to the cooling coil, not shown. At the same time, the solvent resulting from the action of the heater upon the solution is conducted by pipe I I from the heater to a manifold N connected to the inner coils of the heat exchanger, the other ends of which are connected to a manifold N from which the solvent passes through pipe l2, through the float-controlled valve, not shown, to be discharged within the absorber A.

The refrigerant vapor from the cooling coil is returned by pipe l3 to the absorber. Steanris supplied to the heater: H through pipe 14 from a' source of steam, not 'shown, with the condensate I therefrom' returned by pipe Hi to said sc' urce. ;Co oling watefis supplied from thecomrnercial the rectifier, and after passing through-thereotifler, is conducted by pipe l8 to the sewer or returned to the water tower, as the case may be.

A pipe l9 branching from pipe ll conductspooling water to the condensenwhich, after passing therethrough, is conducted by pipe 2B to join-the pipe 18 leading from the rectifier R. This is the normal cycle of operation of the absorption re-e rfrigeration apparatus, illustrated in Figure 1 and monofiuoromethane, or a chemical of similar characteristics, as a refrigerant, as disclosed in applicants prior co-pendingapplication Serial No. 756,977, filed December 11, 1934, due to the characteristic-s of the specified solvent and refrigerant, the low side-or that part of the system including the cooling coil and absorbermay be pumped to a vacuum of 20" or more by closing the usual discharge valve into the cooling coil and continuing the operation of the circulating pump, and the liquid refrigerant may be drained from the condenser, thereby makingit possible to remove the charge of solvent with the relatively small amount of refrigerant held in solution from the system or apparatus without any appreciable loss of refrigerant. In order to eflfect a gravity draining of said charge of solvent, an improved heat exchanger has been provided which possesses other advantages as well. I

The improved heat exchanger is formed, as shown in Figures Z'and 3,0f a pluralityof horizontal rows of similar'coils of pipes 2| arranged one above the other with each coil having the convolutions thereof lying in the same horizontal plane and each coil 25 smaller pipe 22 spaced apart from the interior of each convolution. The outer ends of the outer coils 21 of each horizontal row are connected to a vertical manifold M and the inner ends of said coils 2i are connected to a vertical manifold M.

The inner ends of the smaller inner pipes 22 in each row are extended through vertical manifold M and are connected toa vertical manifold N and the outer ends of the pipes 22 are extended through the vertical manifold M and are connected to a vertical manifold N. The superimposed double coils ofpipes 2i and 22 are mounted within the rectangular casing I and the space between the coils and between the coils and casing is preferably packed with a desirable insulation material.

The manifold M connected with the outer ends of the outer pipe 2| of each coil in each row is provided with a drain cock D extending from the bottom thereof and projecting through the casing, as shown in Figure 3, and the manifold N' connected with the outer ends of the smaller inner pipes 22 in each row is also provided with a similar drain cock D extending from the bottom thereof and projecting through the casing I, as'shown in Figure 2. a

The improved heat exchanger being contained within the casing l which supports the other parts of the apparatus'thereabove with the manifold M connected by the pipe I to the discharge side of the solution pump P and the manifold M is connected through pipes 2?, manifold N, and pipe l l to the lower portion of the interior of the heater H. After the liquid refrigerant has been drained in the system.

containing therein a The heat exchanger, constructed as disclosed herein, not only provides a compact unit but also a most eflicient one as the hot solvent from the heater H enters the inner ends of the small coils 22 from the manifold N and passes through the embracing convolutions toward the periphery to v the outer manifold N with a negligible loss of heat with relation to the small amount of insula tion. Furthermore, due to the low pressure dif- -fied herein, it is essential to reduce the pressure drop through the heat exchanger to the minimum possible for a given size tube, which is accomplished by this improved heat exchanger and which carries more solution for a given pressure drop through a coil of given length and diameter than a coil of equal length and diameter wound on a constant diameter or one using return bends. From a manufacturingstandpoint, not only is a heat exchanger unit constructed in accordance with this invention less costly than the conven-- tional commercial form, but also allows the ready connection of units one above the other for apparatus of a wider range of capacity than the standard single unit.

What I claim is:

1. In an absorption refrigeration apparatus including an absorber, a solution circulating pump, a heater and a condenser, .the combination with a unit heat exchanger including a plurality of horizontal rows of coiled pipes arranged within an enclosed rectangular base supporting all of the first-named elements above the upper surface of he base.

2. The structure of claim 1, wherein each coil includes a smaller enclosed pipe, and wherein the outer ends of the larger coils are connected through the top ofthe base to the solution pump, the outer ends of the smaller pipes are connected through the top of the base to the ab through the top of the base'to the solution pump, the outer ends of the smaller pipes are connected through the top of the base tothe absorber with the inner ends of the larger pipes connected through the top, of the base to the upper portion of the heater and the inner ends of the smaller pipes connected through the top of the base to the lower portion of the heater, and wherein the outer ends of the larger and smaller pipesare each provided with a drain cock extending through the side wall of the base whereby the system may be drained by gravity.

4. In an absorption refrigeration apparatus, an enclosed rectangular casing, an absorber. a solution circulating pump, a heater and a condenser all mounted above and upon the top of said casing as a base, and'a heat exchanger arranged within said casing having connections passing through the top of said casing to the said elements supported thereabove. I

GLENN F. ZELLHOEFER. 

